Genesys Cloud custom object schema 400 in Go

NICE CXone API & Integrations
1

Trying to automate custom object schema definitions in Go and the API is rejecting my payload.

payload := map[string]interface{}{
 "name": "CampaignLog",
 "fields": []map[string]interface{}{{"name": "AgentId", "type": "lookup", "lookupObject": "User"}},
}

The PUT /api/v2/customobjects/schemas returns a 400 with Field type mapping invalid. It’s complaining about the lookup reference even though the target object exists.

2

Honestly, automating custom objects for shift swap tracking is a headache because Go’s default JSON marshaller flattens the lookup reference into a generic object. It’s strict about the nesting for the schema endpoint. When you’re pushing definitions for agent preference overrides or schedule adherence logs, you’ll hit this wall constantly. The API expects the lookupObject and relationshipType to sit inside a dedicated reference block, not loose in the field map.

Try restructuring the payload to match the exact schema definition format:

payload := map[string]interface{}{
 "name": "CampaignLog",
 "fields": []interface{}{
 map[string]interface{}{
 "name": "AgentId",
 "type": "lookup",
 "reference": map[string]interface{}{
 "lookupObject": "User",
 "relationshipType": "one",
 },
 },
 },
}

The workaround is just creating the object manually in the WFM console first, then pulling the raw JSON from the browser network tab. Saves hours of trial and error. The relationshipType field is mandatory for any lookup, and leaving it out triggers that 400 immediately. Also double check that the target object actually exists before the PUT request fires. The automated schedule adherence checks break if the reference points to a deleted custom object.

Keep the version header out of the request body. The endpoint handles versioning automatically. Miss that and the whole publish cycle stalls out.

3

Are you targeting a specific org region, or is this a global deployment? The validation engine sometimes behaves differently depending on the environment.

There is a strict gotcha with custom object lookups that catches most automation scripts. The API does not accept lookupObject at the root level of the field definition. It requires a dedicated reference object, and the casing must match exactly. Missing the relationshipType field is another common trigger for that 400 response. The system also validates the target object’s API name against the org’s active custom objects list before accepting the schema. Pretty easy to trip over if you’re pulling straight from the swagger spec. Might take a second to propagate. The cache doesn’t always refresh immediately.

  • The type must remain lookup.
  • The reference block needs lookupObject and relationshipType nested inside it.
  • relationshipType expects ONE_TO_ONE or ONE_TO_MANY.
  • The lookupObject value must be the exact API name, not the display name.

The Resource Center documentation for custom object schemas outlines this structure, but it is easy to miss when reading quickly. A recent community post on schema validation failures pointed out that Go’s default JSON encoding often drops null values or flattens nested maps unless omitempty is handled carefully. You’ll need to define a strict struct or use a typed map to preserve the hierarchy. See the Custom Objects API Reference article in the Resource Center for the exact payload requirements.

payload := map[string]interface{}{
 "name": "CampaignLog",
 "fields": []interface{}{
 map[string]interface{}{
 "name": "AgentId",
 "type": "lookup",
 "reference": map[string]interface{}{
 "lookupObject": "User",
 "relationshipType": "ONE_TO_ONE",
 },
 },
 },
}

The validation panel highlights the reference block requirement in red when it is missing. The rate limiter on this endpoint is also quite aggressive during off-peak hours.